There aremany kinds of sales. For example, a back-to-schoolsale is heldnear the beginningof the schoolyear. Parentscansave money on clothesandschoolsuppliesfortheir children.
To make things fair, we chose regularly replenished items that all three retailers sell, and we didn't include sale items. (While there are back-to-school sales galore right now, January is prime time for office-supply sales.) To bake in the effect of bulk purchasing, we chose 10 of the largest package of each item.